Magnum One/Magnum One (Mid-American Digital) (Disc Manufacturing).iso/d21/qostnote.arc/AB_PLUS.TEC

Text File | 1990-07-05 | 5.4 KB | 105 lines

ID:AB Intel AboveBoard Plus
DESQview Technical Note

Q:  How do I set up my Intel AboveBoard Plus to best support
    DESQview?

The Intel Above Board Plus supports in hardware many of the
features of the EMS 4.0 software specification that DESQview
would like to use.

It is capable of mapping EMS memory below the 640K barrier and
also of mapping EMS memory into high memory addresses above 640K
and below 1 Megabyte.

Obtaining these features, however requires that the board be set
up in specific ways, and there are some restrictions in the way
the board and driver work that are important to understand.

1.  Backfilling Motherboard Memory:  First, as in the examples
given in the Appendix B of the DESQview manual for Enhanced
Expanded Memory Boards, if you want to have large expanded memory
partitions in which you can multi-task programs, it is necessary to
disable motherboard memory and have the AboveBoard Plus fill
memory out to 640K.  The lowest the AboveBoard Plus will place
EMS4 pages is from 256K, so it is not to your advantage to
backfill any lower than that, even if your machine will support
backfilling from a lower address.  If your machine will allow the
board to fill out from 256K, you will be able to get expanded
memory partitions of 384K.  Unlike the examples in the manual
shown for EEMS cards, the partitions will be 384K regardless of
the type of video card you have as the Intel hardware will not
allow for any EMS expanded memory pages to be mapped into the
video areas.

Once the board is backfilling motherboard memory addresses,  one
very important configuration item remains relative to the driver.
You must specify the "MC" (it means Map Conventional) parameter
to the EMM.SYS driver.  Reference to this parameter is somewhat
buried in the Intel manual, but this parameter must be specified
in order to have the driver set expanded memory pages in the
256K-640K range.
2.  Set the "Page Frame" as low as possible:  The AboveBoard Plus
driver will only map memory above 640K as one contiguous block,
starting with the original 64K EMS page frame.  Any other memory
which to be mapped must be directly above and contiguous with the
page frame.  This perhaps might be changed in a future release of
the driver as other EMS 4.0 drivers are not so restrictive as to
where the additional memory resides.

Because of this requirement, and because the Intel installation
usually defaults the page frame to a "D000" address,  memory
addresses that might be mapped are often bypassed.  To get best
use from the memory, it is generally best to set the page frame
as low as possible.

We have determined that the easiest way to do this is to change
the CONFIG.SYS file so the the frame assignment (usually D000) is
set to C000.  While it is often the case that a C000 page frame
setting might be in conflict with video ROMS, or other installed
devices, it is our observation that the Intel driver generally
detects these devices and on boot will determine that the setting
is inappropriate and will select instead the lowest frame setting
that is free - just what we wanted.  This method, while easy may
not be fool proof, so if you encounter difficulty with the frame
the Intel driver selects, you will have to do some digging into
your hardware documentation to see what area might be available.

3.  Install the QEXT.SYS driver:  Assuming you have an AT, you
can configure some of the Intel AboveBoard Plus memory as
exTENDed memory.  By loading the QEXT.SYS driver in your
CONFIG.SYS file (see page 148 in the DESQview manual), this
driver allows you to take 60K of extended memory and make it
available for running some of DESQview's code, thus lowering the
overhead of DESQview in DOS and making your Maximum Available in
Conventional Memory, as shown by Memory Status 60K bigger.

Now the bad news.... The Intel board only allows you to configure
extended memory in increments of 512K, so in order to get memory
to support the 64K QEXT.SYS driver, you will need to set up at
least 512K of extended memory.  The remaining memory might be
used as a VDISK, or by a disk cache, but will not be available as
expanded memory.  If you are going to allocate this memory, you
will probably want to have quite a bit of memory installed on the
Intel board (say 2 Meg), in order to make this worthwhile.  Intel
has recently begun shipping boards which can allocate memory in
128K segements, and an upgrade for existing boards is available.

If you have other extended memory on the machine, then your
problem should be solved.  You would simply install the QEXT.SYS
driver and as long as the extended memory starts at 1 megabyte
(1024K), QEXT will use it.  This would allow you to keep all of
the memory on the AboveBoard Plus as exPANDed memory.

As is usual, when using an expanded memory system, you will want
to load DESQview using the XDV.COM loader as indicated on page
139 of the DESQview manual. The settings above should allow you
to get the best memory sizes for DESQview.  Your Memory Status
program will probably show figures somewhat less than listed in
the DESQview manual.  This is because the AboveBoard Plus will
not map into video memory area,  but the memory obtained in the
windows should be adequate for most purposes.

        Copyright (C) 1990 by Quarterdeck Office Systems
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